With concerns over the home use of pyrethroid insecticides for mosquito control, researchers in Thailand have developed a validated method for analyzing cis/trans-permethrinic acid in powdered milk.
Pyrethroids are naturally occurring insecticides that are synthesized to make mosquito coils and sprays for home use. These pesticides may be bioaccumulated in women’s bodies and may be excreted as metabolites or parent products in breast milk. This study replaces powdered milk as an analogue of human breast milk.
Milk was prepared from the formula according to the manufacturer’s instructions and used as a matrix for fractions (in acetone) at concentrations ranging from 0.05 – 10.00 µg/mL. β-Naphthol, dissolved in toluene, at 0.01 µg/ml was used as an internal standard. 50 µL of all standards, QC, and samples were added to 1.5 mL centrifuge tubes and evaporated to dryness at 40 °C. 20 µL of Derivatization Reagent mtbstfa ((N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide, 98%) UCT, Inc. (MTBSTFA-0-100) and 50 µL of IS was added to each dry tube and sonicated for 10 min. The samples were incubated at 80 C for 10 min before being injected into the GC/MS.